323 Masking mountains away from sky

…In this movie, I'll show you how to create that mask that I use to…distinguish the mountains from the sky in…order to create this final two exposure composition.…I'd like to tell you that this is…a completely automated process, that there's nothing to it.…But it actually requires a fair amount of manual labor.…And that's because if you zoom on in to the image, you can see…that it's easy to distinguish the trees from the sky, as well as the rocks.…The problem is these little patches of snow, which are every bit…as bright and neutral as the clouds up here in the sky.…

So, we are going to have to engage in some actual work here.…The first step is to go ahead and select the…brighter layer, which is the brighter of the two exposures.…And then, armed with the rectangular marquee tool,…up here at the top of the tool box,…right-click inside the image window and choose Duplicate…Layer, and go ahead and set document to New.…And then I'm going to name this guy, New Mountain Mask, like so.…Just so we can tell it apart from the other one.…